Abstract:
The lidar profiles density, temperature, wind velocity and aerosol loading from the lower troposphere to the upper mesosphere, depending on operating mode.

Two main measurement techniques are employed. Firstly, traditional Rayleigh backscatter analysis yields temperature profiles above the top of the stratospheric aerosol layer (greater than about 27km altitude). The temperatures are obtained ... from lidar-derived density profiles, calibrated with in-situ radiosonde data below 40km altitude, using the standard hydrostatically-constrained perfect gas law model. When available, hydroxyl-layer temperatures obtained locally by a Czerny-Turner spectrograph are used as an upper boundary condition on the temperature retrieval algorithm. Rayleigh backscatter can be detected from altitudes as high as 100km, although useful temperatures are normally limited to below 80km. Observations of rotational-vibrational Raman backscatter from molecular oxygen or nitrogen are used to extend the temperature profiles into the lower stratosphere and upper troposphere. Profiles of aerosol-loading are derived from standard scattering-ratio analysis, allowing identification of clouds in the upper troposphere, stratosphere (Polar Stratospheric Clouds) and mesosphere (Polar Mesospheric Clouds).

Secondly, spectral scans of laser backscatter are obtained with a high-resolution Fabry-Perot spectrometer. These are used to infer the line-of-sight wind speed and temperature by using the Doppler effect. Observations along 'cardinal point' lines-of-sight provide information on wind direction. In general, Doppler measurements are restricted to altitudes below about 70km based on signal detection considerations. Some information on aerosol loading is obtained from analysis of the spectral properties of the backscatter.

The lidar is capable of both day and night measurements covering a large altitude range, and in so doing will provide information for the study of climate change and a range of atmospheric phenomena on a variety of spatial and temporal scales.

Taken from the 2008-2009 Progress Report: Progress against objectives: At Davis, lidar measurements of temperature and aerosol properties were acquired for the troposphere, stratosphere and mesosphere. Additionally, ozone data were acquired for the troposphere and lower stratosphere.

Ongoing analyses of these data is providing new information on the composition, dynamics and climate of the polar atmosphere. During the reporting period, continued progress was achieved in international collaborative studies of Polar Stratospheric Cloud microphysics as part of the International Polar Year, and measurements of Polar Mesospheric Clouds for the Aeronomy of Ice in the Mesosphere (AIM) satellite mission. Both of these activities contribute to all 4 goals of the project.

Taken from the 2009-2010 Progress Report: Progress against objectives: New data were obtained for the study of the long-term climate in the Antarctic middle atmosphere (5-95km altitude), and atmospheric phenomena under extreme physical conditions. The highlights were: (1) Detailed measurements of ice clouds in the summer mesopause region for validation of climate models. (2) Further measurements of the properties and dynamics of Polar Stratospheric Clouds for research aimed at improving projections of the recovery of the Ozone Hole. (3) Initial measurements for a new study of the interactions between the troposphere and stratosphere which is aimed at improved knowledge of climate processes in the tropopause region.

Quality
Data collected by the LIDAR system include the density, temperature, wind velocity and aerosol loading as a function of altitude from near the ground (typically, above about 15 km altitude) to the upper mesosphere. The spatial and temporal resolutions of the data depend on the operating mode of the lidar, time of day, and local meteorological conditions.

... Taken from the 2008-2009 Progress Report: Field work: All fieldwork was undertaken at Davis. During the review period, the lidar was operated as often as practicable during suitable weather conditions, with approximately 1200 hours of data collected between June 2008 and April 2009. The fieldwork milestones were; (1) July-October 2008 - special high resolution observations of Polar Stratospheric Clouds, coordinated with observations of the CALIPSO satellite mission and flights of balloon-borne ozonesondes, (2) November 2008 to February 2009 - special day and night profiling for Polar Mesospheric Clouds in coordination with MST radar operations and AIM satellite overpasses, (3) ongoing - coordination of lidar observations with ozonesonde and special radiosonde flights provided by the Bureau of Meteorology, and Antarctic lidar measurements conducted at Dumont d'Urville (by France) and McMurdo (by Italy). Progress with data collection met expectations.

Laboratory activity/analysis: Analysis activity, including data checking, was undertaken primarily at AAD Head Office. Additional data checking was performed at Davis and in the case of ozonesonde data, by the Bureau of Meteorology in Melbourne. The progress of this activity has been as expected. The main activities were (1) basic data checking to ensure that the instrument and data collection software was performing as expected, (2) validation of temperature data where possible using in-situ measurements from BoM radiosondes and soundings from satellite missions (Aqua, TIMED, Aura, COSMIC, ACE) and assimilated global data sets (UKMO, NCEP, GEOS4), (3) analysis of backscatter from Polar Stratospheric Clouds (PSC) and Polar Mesospheric Clouds (PMC), and (4) analysis of ozone data from ozonesondes. All of these activities are on-going.

Taken from the 2009-2010 Progress Report: Field work: All fieldwork was undertaken at Davis. The lidar was operated by Dr Simon Alexander (2009 wintering Head Office Research Scientist) and Jeff Cumpston (2010 wintering Lidar Scientist), with additional involvement by Dr Andrew Klekociuk (2009/10 summer), Theo' Davis (La Trobe University, 2008/09 and 2009/10 summer) and Roland Stehle (2009 wintering engineer). During the review period, the lidar was operated as often as practicable during suitable weather conditions, with approximately 385 hours of data collected between July 2009 and April 2010. The amount of data collected was lower than recent years.

The fieldwork milestones were; (1) Jul-Oct 2009 - special high resolution observations of the Upper Troposphere- Lower Stratosphere using the Raman technique for temperature profiling, (2) Nov 2009 to Feb 2010 - special day and night profiling for Polar Mesospheric Clouds in coordination with MST radar operations and AIM satellite overpasses, (3) ongoing - coordination of lidar observations with ozonesonde and special radiosonde flights provided by the Bureau of Meteorology, and Antarctic lidar measurements conducted at Dumont d'Urville (by France) and McMurdo (by Italy).

A high power laser was acquired to replace the existing laser to improve operational reliability; the new laser was successfully installed at Davis during the 2009/10 summer.

Laboratory activity/analysis: Analysis activity, including data checking, was undertaken primarily at AAD Head Office. Additional data checking was performed at Davis and in the case of ozonesonde data, by the Bureau of Meteorology in Melbourne. The progress of this activity has been as expected. The main activities were (1) basic data checking to ensure that the instrument and data collection software was performing as expected, (2) validation of temperature data where possible using in-situ measurements from BoM radiosondes and soundings from satellite missions (Aqua, TIMED, Aura, COSMIC, ACE) and assimilated global data sets (UKMO, NCEP, GEOS5), (3) analysis of backscatter from Polar Stratospheric Clouds (PSC) and Polar Mesospheric Clouds (PMC), and (4) analysis of ozone data from ozonesondes. All of these activities are on-going.

Evtushevsky, O., A. Klekociuk, A., Grytsai, A., Milinevsky, G and Lozitsky V. (2010). Influences on the tropopause in the polar regions by the troposphere and stratosphere during winter and spring, International Journal of Remote Sensing (accepted).